Introduction to Rust - NU Workshop

main.rs

fn main() { // 'a
    // Printing to the screen
    println!("Hello, world!");

    // Variables & mutability
    let mut x: u128 = 1;
    x = x + 1;
    println!("x is {x}");

    // Arrays, vectors, ranges, and loops
    let arr = [3, 4, 5];
    let mut my_vec = vec![];
    my_vec.push(1);
    my_vec.push(2);
    my_vec.push(3);
    for x in my_vec {
        println!("Value: {x}");
    }

    for i in 0..=10 {
        println!("{i}");
    }

    let mut x = 0;
    while x < 10 {
        x += 1;
        println!("{x}");
    }

    let mut x = 0;
    loop {
        x += 1;
        println!("{x}");
        if x >= 10 {
            break;
        }
    }


    // Control flow
    let val = if 3 < 4 {
        println!("hello");
        1
    } else {
        println!("goodbye");
        0
    };

    let x: Option<i32> = Some(4);

    let answer = x.unwrap();
    println!("{answer}");

    match x {
        None => println!("x is none"),
        Some(some_value) => println!("x is some({some_value})"),
    }

    let answer = if let Some(some_value) = x {
        some_value
    } else {
        42
    };

    let v = std::env::var("MY_VAR").ok();
    println!("{v:?}");

    // Functions
    fn my_function() {
        println!("hello from my_function");
    }

    fn my_calculation() -> i32 {
        8 + 1 * 4 / 5
    }

    // Functions with owned vs. borrowed arguments
    fn say_hello(name: &String) {
        println!("Hello, {name}!");
    }

    let name = "Jacob".to_string();

    say_hello(&name);
    say_hello(&name);

    // Lifetimes
    fn longest<'a>(first: &'a String, second: &'a String) -> &'a String {
        if first.len() > second.len() {
            first
        } else {
            second
        }
    }

    let x = "very long string".to_string();
    { // 'b
        let y = "shrt".to_string();

        let longest_string = longest(&x, &y);
    }
}